This invention relates to automatic doffing apparatuses for textile spinning machines and the like, and more specifically relates to a stop-motion system for an automatic doffing apparatus having a bobbin feeding and transporting section of the general type disclosed in U.S. Pat. No. 3,870,195. Other prior United States patents of possible relevance are U.S. Pat. Nos. 3,795,343, 3,698,536, 3,601,283, 3,576,094, 3,531,016 and 3,410,452.
In an automatic doffing apparatus of the type manufactured and sold by Platt Saco Lowell Corporation, tubular bobbins are at desired times transported from supply sources, located within an end-cabinet of the spinning machine serviced by the apparatus, to upstanding peg elements upon belt-like conveyors extending along and movable longitudinally of opposite sides of such spinning machine. At each side of the apparatus, the bobbins are transported first by a cradle-like transporting member from an associated supply source to a bobbin-orienting device, and then are transported by a cage-like transporting member from the orienting device to the pegs of the associated conveyor. During normal operation of the apparatus all four of the bobbin transporting members undergo continuous oscillatory movement in synchronous relationship to each other, to an oscillatorily-drive member, and to the two conveyors of the apparatus. Such mode of operation is more fully described, with respect to the components adjacent one side of the doffing apparatus, in previously-mentioned U.S. Pat. No. 3,870,195.
There are significant advantages inherent in operation of an apparatus of the described type on a continuous-movement basis, as opposed to an intermittent-movement basis. Certain automatic doffing apparatuses which operate on an intermittent-movement basis employ the use of the one or more switch elements positioned closely adjacent the paths of travel of the bobbins being transported, and actuable by such bobbins. This is undesirable, and the continuous-movement apparatus of the type presently in question neither requires nor employs any switch elements actuable by the bobbins being transported. Additionally, an apparatus of the present continuous-movement type performs its bobbin transporting functions more efficiently and rapidly than one which operates on an intermittent-movement basis. On the other hand, the rapidity of operation of an apparatus of the subject type also makes it highly desirable that such operation be promptly halted if for any reason there should be a significant variation in the regular, synchronous oscillatory movement of one or more of the bobbin transporting members. Such a variation in the movement of one of the transporting members might be occasioned by either malfunction of a component of the apparatus or, as would more normally be the case, by a blockage caused by a bobbin-jam within the apparatus. In the case of either eventuality, prompt cessation of the operation of the apparatus is highly desirable in order to prevent possible structural damage to its components and in order to minimize the time and manual effort required to restore the apparatus to its normal operating conditions and status.